Automatic ice maker control means



'Aug. 25, 1970 T M 3,525,232

AUTOMATIC ICE MAKER CONTROL MEANS Filed Aug. 30, 1968 2 Sheets-Sheet 1 H\S ATTORNEY Aug. 25, 1970 D. N. TOMA 3,525,232

AUTOMATIC ICE MAKER CONTROL MEANS Filed Aug. 30, 1968 2 Sheets-Sheet 2INVENTOR.

DANEL; N- TOMA H l S ATTORNEY United States Patent O US. Cl. 62-137 9Claims ABSTRACT OF THE DISCLOSURE A household refrigerator including anautomatic ice maker, an ice bin for storing ice pieces produced by the.

BACKGROUND OF THE INVENTION Automatic ice makers of the type presentlyprovided in household refrigerators broadly include means forautomatically filling a plurality of mold cavities w th water,discharging the ice pieces formed in the cavities into a movable orremovable storage bin or receptacle and then repeating this cycle.Ice-level sensing means are included for terminating the automaticoperation of the ice maker when a predetermined level of ice in thestorage receptacle has been reached. A known level sensing means of thetype described in Pat. 3,331,215Shaw, comprises a feeler arm mechanismmovable at some time during each cycle of operation of the ice maker tosense or feel the ice accumulation in the bin and to stop the operationof the ice maker when a desired quantity of ice has been stored. Inorder that such arm mechanism will not interfere with access to the icepieces stored in the bin or with the discharge of ice pieces into thebin, it has been necessary to restrict the size and shape thereof sothat it actually senses the level of ice at only one point or over arelatively small area of the bin. Also, since the feeler arm mechanismis associated with the ice maker, it senses the level of ice near theice maker or more specifically immediately below one portion of the icemaker. Thus, once the ice accumulated in the bin fills up to a pointwhere the feeler arm contacts the ice at that portion of the bin sensedby the feeler arm, the automatic operation of the ice maker is stoppedregard- 3,525,232 Patented Aug. 25, 1970 restricted to fixed bins orreceptacles and both the light source and the receiving unit have beenpermanently built into or mounted on the walls of the bin. In additionsince the photocell sensing has employed a beam of light directed fromthe light source to the photocell, the level sensing has been restrictedto the ice in the line or path less of the level of ice in the remainingportions of the bin.

It has also been proposed, as described in Pat. 3,045,445MacLeod, toemploy either thermostatic sensing means or photocell means for sensingthe accumulation of a predetermined quantity of ice within a storage binand thereupon de-energize an ice maker. A thermostatic sensing means isnot satisfactory for household refrigerators for a number of reasonsincluding the fact that different users operate their freezers atdifferent temperatures and the frequent door openings of the door to thefreezer compartment adversely affect the operation of a thermostaticsensing means. The use of photocell means, as described in the MacLeodpatent, has been of this beam.

SUMMARY OF THE INVENTION The present invention is directed to animproved ice level sensing means particularly adapted for use inconnection with a movable or removable ice bin and is more specificallyconcerned with a light operated sensing means forming part of an icemaker control circuitry designed to assure the proper operation thereofunder all normal conditions of use of the freezer compartment of thehousehold refrigerator containing the ice bin.

In accordance with the illustrated embodiment of the invention, there isprovided a household refrigerator including a freezer compartmentcontaining a storage bin for collecting ice pieces produced by an icemaker. The storage bin has an opening in one wall thereof. A lightsensitive means is positioned outside of the bin adjacent the openingwhere it is sensitive to light passing through the opening and means areprovided for illuminating at least that portion of the freezercompartment containing the ice bin. The light sensitive means is part ofthe ice maker control circuitry which is designed so thatthe ice makercontinues to operate until there is a predetermined decrease in theintensity of the light passing through the opening due to accumulationof ice in the bin. Preferably the opening is an elongated horizontalslot and the light sensitive means includes a light collecting barcoextensive with the slot. Additional aspects of the illustratedembodiment of the invention include means fon interrupting the operationof the .ice maker whenever the storage bin is moved from its icereceiving position, means for de-energizing the light source when thedesired amount of ice has accumulated in the bin and means com prisingthe usual light for illuminating the interior of the freezer compartmentwhen the access door thereto is opened for re-energizing the ice makerwhen the ice level has again been lowered below the stopping level.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing FIG. 1 is afront elevational view of the freezer compartment portion of a householdrefrigerator;

FIG. 2 is a sectional view taken generally along lines 22 of FIG. 1;

FIG. 3 illustrates one form of light collector bar suitable for use topractice the present invention;

FIG. 4 is a top view of a portion of the collector bar of FIG. 3; and

FIG. 5 is a schematic diagram of electrical circuitry for controllingthe operation of the ice maker.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIGS. 1 and 2of the drawing there is illustrated a household refrigerator including afreezer compartment 1 having an access opening at the front thereofclosed by means of a closure member in the form of a door 2. Anautomatic ice maker 3 is mounted in an upper portion of the freezercompartment in a position to discharge ice pieces into a storagereceptacle 4 suitably supported below the ice maker 3. It will beunderstood that the ice maker may be any of the well known typespresently used in household refrigerators, the illustrated ice makerbeing generally of the construction shown in the aforementioned ShawPat. 3,331,215 except for the substitution of the ice level controlmeans of the present invention for the feeler arm mechanism of the Shawstructure.

Also, while in the illustrated embodiment of the invention thereceptacle 4 is illustrated as being supported on a bottom wall of thefreezer compartment, in the adaptation of the invention to arefrigerator which includes a storage drawer within the freezercompartment, the receptacle 4 may be carried by the drawer structure ina position such that when the drawer is closed, the receptacle 4 will bein an ice receiving position below the ice maker 3.

The illustrated receptacle 4 is of a generally rectangular shape whilethe bottom wall 5 of the freezer includes one or more projections orstops 6 for engaging the side and rear walls of the bin to properlyposition the bin below the ice maker 3. Since the ice maker 3 issupported adjacent the one. side wall 9 of the freezer compartment, thisside wall 9 prevents lateral displacement of the receptacle in thisdirection.

The receptacle 4 is, of course, of a limited storage capacity. Thereforeit is necessary to interrupt the operation of the ice maker before theamount of ice discharged into the receptacle exceeds its storagecapacity. However it is also desirable to avoid premature stopping ofthe ice maker. When a mechanical means such as a feeler arm like thatdescribed in the aforementioned Shaw patent is employed for terminatingthe operation of the ice maker, the operation is sometimes interruptedbefore the full storage capacity of the receptacle is used. For example,employing a receptacle such as that shown in FIGS. 1 and 2 of thedrawing and a mechanical feeler arm such as that disclosed in the Shawpatent, the feeler arm will sense the level of ice below the open ordischarge side of the ice maker 3 that is adjacent the receptacle sidewall 10. Since the ice pieces are discharged into the portion of thereceptacle adjacent this wall, they tend to pile up in this area so thatthe operation of the ice maker may be interrupted even though the iceproduction of a few additional cycles of operation of the ice makercould be accommodated in the receptacle since such additional ice pieceswould tend to roll or slide from the top of the pile downwardly beneaththe ice maker and in the direction of the left wall 11 0f thereceptacle. While such premature stopping could be avoided by centeringthe receptacle relative to the point at which the ice pieces aredischarged into the receptacle, this would tend to waste the freezerstorage compartment volume between the receptacle and the freezer wall9.

In accordance with the present invention, there is provided meansoperatively associated with the receptacle rather than with the icemaker for terminating the ice maker operation when the bin contains theoptimum amount of ice. More specifically, the ice sensing meanscomprises photoelectric means comprising a source of illumination forthe interior of the freezer compartment or at least that portion thereofadjacent one 'wall thereof and an opening in that wall adjacent thelight sensitive means. When the intensity of the light passing throughthe opening and sensed by the light sensitive means decreases due to theaccumulation of ice pieces in front of part or all the opening, theoperation of the ice maker is interrupted.

The light source may be mounted at any convenient point above andadjacent the receptacle. In the illustrated embodiment of the invention,the light source comprises a small bulb 14 mounted by means of a bracket15 on the discharge edge or side of the automatic ice maker 3 above thereceptacle 4. This bulb 14 serves to illuminate at least that portion ofthe freezer compartment 1 adjacent the receptacle 4. More specificallyit illuminates the interior of the receptacle 4.

One wall of the receptacle, preferably the wall 11 spaced the greaterdistance from the area of the receptacle into which ice is discharged bythe ice maker 3 includes at least one opening 16 which is preferably inthe form of an elongated horizontal slot as illustrated in FIG. 2 of thedrawing. This slot is spaced from the top of the wall 11 a distance suchthat when the ice has accumulated to approximately the height ofopposite Wall 10', the ice pieces at the wall 11 will begin to cover orpartially cover the opening 15 and thereby decrease the amount of lightpassing through the slot opening 15.

Means sensitive to the light passing through the opening '15 ispositioned on the outside of the wall 11 and in the illustratedembodiment of the invention this means is mounted on the freezer wall 9.The light sensitive means may be the usual photoelectric cell or any ofthe well known light-activated semiconductors such as a light activatedSCR or a light activated silicon controlled switch or a phototransistor.In accordance with the illustrated embodiment of the invention, aphototransistor is employed as the light sensitive means and thiselement, generally indicated by the numeral 17, is mounted within arecess 18 in one end of a light collecting bar 19' which issubstantially coextensive with opening 15. A phototransistor is apreferred means for sensing the amount of light passing through theopening 15 since it combines both functions of a photocell andtransistor in one unit.

The light sensing element or bar 19 is a well known means for collectinglight and transmitting that light to a specific point. The bar may bemade for example of methyl methacrylate resin and has a light receivingface or front side 20 which is positioned opposite the opening 15 whilethe remaining sides and rear wall of the bar are coated with a suitableopaque paint or other coating as shown in FIGS. 3 and 4. If desired,means may also be provided for restricting the amount of light reachingthe light bar along a path between the freezer wall 9 and the wall 11.For example, a flange 21 may be provided on the wall 11 immediatelyabove and in shielding relationship to the collector bar 19. Also therear wall of the bar may be provided with a series of arcuate grooves orslots 22 designed to reflect light and increase the transmission oflight to the end of the bar containing the phototransistor 17.

Using a light collector bar in combination with a 'horizontal slot 19,the bar will scan a substantial length of the storage bin and thereforesense a build-up of ice at any point along its length as well as providea control responsive to an average rather than a point or local buildupof ice.

The operation of the light sensing means in controlling the stopping ofthe ice maker when a. predetermined amount of ice is accumulated in thebin 4 will become more apparent from consideration of the controlcircuit shown in FIG. 5 of the drawing. The elements or components ofthe illustrated circuit are only those essential to the operation of theice maker insofar as the photoelectric sensing control is concerned. Theice maker components included in the diagram of FIG. 5 and more fullydescribed in the aforementioned Shaw patent include a motor 26 fordriving the ice maker timing ejection and water fill mechanism, a moldheater 27 for warming the walls of the ice mold to facilitate therelease of the ice pieces, and a thermostatic switch 28 for sensing themold temperature and initially energizing the motor 26 and the heater 27upon the formation of ice in the ice maker mold. The motor 26 drives acam 29 operating a plurality of switches during an ice harvesting cycle,one of which energizes and opens a solenoid valve 30 for supplying afresh charge of water to the ice maker mold.

When the thermostatic switch 28 senses a predetermined below freezingtemperature, it closes and connects both the motor 26 and the moldheater 27 across the supply lines 31 and 32. During initial operation ofthe motor the cam 29 closes a first switch 33 bypassing the thermostat28 to assure continuous operation of the motor 26 and the mold heater 27after the heater 27 has warmed the mold to a point where thethermostatic switch 28 opens. After discharge of ice pieces from themold, the cam 29 closes a second switch 34 for energization of thesolenoid controlled water valve 30 to supply a fresh charge of water tothe mold. Thereafter, rotation of the cam 29 opens both switches 33 and34 de-energizing both the motor and the mold heater which remainde-energized until the thermostat 29 again senses a below freezingtemperature.

To interrupt this automatic ice making cycle when the amount of iceaccumulated in the receptacle 4 has substantially reached the capacitythereof, the phototransistor 17 is part of a control circuit including aDC regulated power supply comprising a voltage regulating Zener diode35, a dropping resistor 36 and a rectifying diode 37 adapted to supply alow DC voltage from lines 31, 32 to the positive line 38 and negativeline 39. The light 14 is connected across the lines 31, 32 through asilicon controlled rectifier (SCR) 41 and also through a circuit whichincludes a heater 42 and a diode 43 in parallel with the siliconcontrolled rectifier 41. The phototransistor 17 is connected across thelines 38, 39 in series with a high resistance 44 between the cathode ofthe phototransistor and the negative terminal 39. The gate 45 of thesilicon controlled rectifier 41 is connected between the cathode of thephototransistor 17 and the resistance 44, the resistance 44 being ofsuch a value that when the phototransistor is conducting, it supplies agating signal to the silicon controlled rectifier to turn that elementon. Additional elements of the circuit include a capacitor 48 and aresistance 49 connected in series with one another and in parallel withthe SCR 41 to protect the SCR from high voltage transients and, ifdesired, a capacitor 50 connecting the gate of the phototransistor 17 tothe line 39 for stabilizing the operation of the phototransistor.

A heater 42 is mounted in heating relationship with the thermostat orice sensor 29 and biases the action of the thermostat 28 by the amountof heat supplied thereto.

In considering the operation of this control circuitry, it may beassumed that the light 14 is on and the level of ice in the bin 4 islow. The light ambient in the area of the freezer compartment containingthe bin 4 is sufficient to maintain the phototransistor 17 on and withthe phototransistor 17 conducting a gating signal is supplied to thesilicon controlled rectifier 41. As a result current continues to flowthrough the light 14 and the silicon controlled rectifier 41 to maintainthe light 14 on. Also with the silicon controlled rectifier 41conducting, it shorts out the heater 42 and with no heat being suppliedby the heater 42 to the thermostat 28, the ice maker operates in itsnormal automatic manner.

When sufficient ice accumulates in the bin 4 to decrease the intensityof the light reaching the phototransistor 17 to a point where thephototransistor no longer conducts, the silicon controlled rectifier 41is turned off with the result that current then flows through the light14 and the heater 42. Sufiicient heat is supplied to the thermostat 28by the heater 42 to maintain the thermostat 28 at a temperature aboveits normal operating temperature or in other words at a temperatureabove that at which it normally closes its contacts to energize the icemaker motor 26 and ice mold heater 27. Thus the automatic operation ofthe ice maker is interrupted. Also, as the heater 42 is now connected inseries with the light 14, the amount of light given off by the light 14is insufficient to trigger the phototransistor on regardless of theamount of ice in the bin 4.

Since the amount of light from the light 14 is insufficient under theseconditions to render the phototransistor 17 conducting, means areprovided for providing the required light to render the phototransistor17 conducting whenever the ice level in the bin has been lowered. Aconvenient source of this re-energizing light is the usual bulb 52provided for normally illuminating the interior of the freezercompartment and controlled by a normally open door switch 53 whichcloses to energize the light 52 whenever the door 2 is open. Thus, eachtime the door 2 is opened, the bulb 52 provides a light ambient in thevicinity of the bin 4. After suflicient ice has been removed from thebin that the intensity of the light reading the phototransistor issufficient to trigger the phototransistor, the silicon controlledrectifier will be gated on and the light 14 will again be fully on whilethe heater 42 will be shorted to return the icemaker to its normalautomatic operation. In order to prevent reactivation of the ice makerby the light from bulb 52 if bin 4 has been removed from the freezercompartment or is in out of position relative to the ice maker, one ofthe AC supply lines 31, 32 includes a bin operated switch 54 so that theice maker circuitry is opened whenever the bin is not in its normalposition.

From the above description, it would seem that there has been providedan ice level control circuit for an ice maker which is independent ofthe position of the ice maker or any mechanical component thereofrelative to the bin and which is adapted or tailored to the shape,capacity and positioning of the bin 4. Also the intensity ofillumination of the light 14 is an indication to the user of whether theice maker is operating and whether the bin is full, not full, or out ofposition.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A household refrigerator comprising an automatic ice maker, a freezercompartment containing a removable storage bin for collecting ice piecesproduced by said ice maker and having an opening in one wall thereof;

control means including means for stopping the operation of said icemaker when the ice collected in said bin at least partially blocks saidopening,

said stopping means comprising illuminating means above said bin forilluminating at least the portion of said compartment including said binand light sensitive means positioned outside said bin adjacent saidopening and responsive to a decrease in the intensity of light passingthrough said opening to a given level for stopping said ice maker.

2. The refrigerator of claim 1 in which said opening is a horizontalslot and said light sensitive means includes a light collecting barsubstantially coextensive with said slot.

3. The refrigerator of claim 1 in which said bin is removably positionedin said compartment and said control means includes switch meansoperable upon removal of said bin to stop said ice maker.

4. The refrigerator of claim 1 in which said illuminating means ispositioned generally above said bin.

5. The refrigerator of claim 4 in which said illuminating means ismounted on said ice maker.

6. The refrigerator of claim 1 in which said illuminating means isrendered ineffective upon stopping of said ice maker by said lightsensitive means and said compartment contains a second periodicallyenergized illuminating means for reactivating said ice maker when theintensity of light from said second illuminating means passing throughsaid slot is above said given level.

7. The refrigerator of claim 6 in which said ice maker includes athermostatic control operable in response to the freezing of watertherein for discharge of ice into said bin and said control meansincludes a heater which is energized to prevent operation of saidthermostatic control when said first illuminating means is de-energized.

8. The refrigerator of claim 6 comprising a closure member forclosing-the access opening to said compartment and in which said secondilluminating means is ener gized when said closure member is opened.

9. The refrigerator of claim 7 in which said control means comprises asilicon controlled rectifier for control- 7 8 ling the operation of saidheater and said light sensitive 3,188,828 6/1965 Wayne 62--140 meanscomprises a phototransistor controlling the gating 3,196,274 7/1965Giordmaine 250-215 X of said silicon controlled rectifier.

References Cited UNITED STATES PATENTS 3,045,445 7/1962 MacLeod 6213762264; 250215 3,120,108 2/1964 Pansing 62140X WILLIAM E. WAYNER, PrimaryExaminer U.S. Cl. X.R.

